Hi, I have an old Aiwa CX-NA50 that I bought in 1998. It's a three CD
(3 CD) mini system. From the beginning it would "reject" certain CDs..
it would spin them a couple of times, with a slight clicking, might
bring up the track directories every once in awhile, but most often
would skip to the next cd. After about a year of this it wouldn't play
CDs much any more at all. It's been sitting in the closet since about
1999. Recently I took it out to play MP3s and XM Radio via an FM
transmitter because the little speakers are excellent.

Today I took it apart and fiddled with the little potentiometer
(potter, pot) inside the machine right next to (behind actually, a few
inches toward the rear of the machine) the laser. It was a chore
getting it apart and I had to take off the side and part of the back.
I turned the little potter about 1/8 turn counter-clockwise, and it
started working and now seems to read and play CDs. Whether this will
"burn out" the laser at some point is not a concern to me since it
wasn't working at all before. I tested it to make sure this was
actually the reason by turning the potter back into the original
position, and sure enough it failed to work again. So I'm reasonably
sure this is what's the matter with it, or a "kludge" to get around
what is really the matter.

Previously I had tried to clean the laser, to no avail. For those of
you who have faulty Aiwa systems you should know that there was a
class-action settlement a few years ago that offered to replair the
systems for free, because many of the systems had this problem. It is
a very common problem. Unfortunately the period of time to take
advantage of that has passed, so now you must do it yourself unless you
simply want to pitch the system or pay money to have someone else do
it.

So if your mini CD player is not reading the discs you put in, you may
want to try this fix. Do this at your own risk.